The sailors of Russia's Caspian fleet have seen little action over the last 300 years but now the war raging in Syria has thrust them into the forefront of Russia's largest military operation abroad since the collapse of the Soviet Union.

Better known for oil drilling and sturgeon smuggling than strategic naval importance, the Caspian Sea bordering Central Asia and the Middle East was an unexpected place for Russia to launch a battery of cruise missile attacks against Islamic State targets in Syria on Wednesday.

But the Caspian Flotilla, founded by Peter the Great in 1722 and headquartered in Astrakhan - a city on Russia's south coast celebrated for its watermelons and dried fish - was the only choice for Russian generals wanting to showcase their military reach in the Syrian conflict.

Obtaining permission to fly missiles through the airspace of NATO-member Turkey was an unlikely prospect and a land-based attack was ruled out by the 1987 Intermediate-Range Nuclear Forces Treaty which prohibits the use of ground-launched missiles with a range of 500 to 5,500 km.

"It was simply the only option," said Ruslan Pukhov, director of the Moscow-based Center for Analysis of Strategies and Technologies.

Russia's air campaign in Syria has caught the United States and its NATO allies off-guard and alarmed Turkey, which sits between the conflict and Russian naval forces on the Black Sea. Ankara says its air space has been repeatedly violated by Russian jets.

A group of four Russian warships launched 26 Kalibr cruise missiles, known by the NATO codename Sizzler, from the Caspian Sea on Wednesday, the first time they had been fired in combat.

The Russian Defense Ministry said the terrain-hugging missiles traveled some 1,500 km (900 miles) to strike their targets and denied U.S. reports that four of the rockets crashed in Iran.

Superpower status

Russia currently stations at least 20 warships armed with missiles, torpedoes and artillery cannons on the Caspian Sea, military observers say, a surprisingly large force given the absence of regional opponents or conflict around a land-locked body of water beloved of Iranian beachgoers.

Pukhov said ships equipped with Kalibr cruise missiles had been operating in the region since 2012.

The Russian Defense Ministry declined to comment on the number or type of vessels deployed. In an online statement it said the fleet was tasked with protecting Russia's regional interests and fighting terrorism.

Defense columnist Alexander Golts said Russia's missile strikes hinged on the Caspian Flotilla's unusual location, separated from Syria by Russian ally Iran and Iraq, which also receives military support from Moscow, as obtaining permission to fly through foreign airspace was one of the main obstacles to the operation.

"It's very simple," said Golts, who is also deputy editor of online newspaper Yezhednevny Zhurnal. "They could quickly reach an agreement with Iraq and Iran but not with Turkey."

Moscow's decision to fire the missiles was motivated by a desire to underline its role as a global power on a par with the United States and NATO, said Igor Sutyagin, senior research fellow at the Royal United Services Institute for Defense and Security Studies.

Missile strikes are typically used to weaken enemy forces ahead of large-scale battlefield assaults or to reach targets inaccessible by air.

Russia has repeatedly said it has no plans to send ground troops to Syria and its air force has been flying sorties over the country for more than a week.

"This was done to look like the Americans, to play the superpower status," Sutyagin said. "It says: take us seriously."